Effect of Low-Level Laser Therapy on Stability of Dental Implants in D3 and D4 Bone Quality: A Split-Mouth Randomized...

Achieving predictable implant stability in low-density maxillary bone (D3-D4) remains clinically challenging because reduced bone density is associated with greater early loss of stability and an increased risk of implant failure. Photobiomodulation (PBM) has been proposed to enhance osseointegration; however, clinical evidence regarding its effect on implant stability in low-density bone remains limited and inconsistent. The aim of this study is to evaluate the effect of 940-nm diode laser photobiomodulation (PBM) on implant stability during early healing in low-density maxillary bone (D3-D4).

This split-mouth, randomized controlled clinical trial included medically healthy adults who required bilateral maxillary implants. A total of 40 implants were placed in 10 participants using a guided flapless protocol. Test sites received 940-nm diode laser PBM immediately after implant placement and at 2-week intervals for 2 months, while contralateral sites served as controls. Implant stability was measured using resonance frequency analysis and expressed as implant stability quotient (ISQ) at baseline (T0), 2 months (T1), and 3 months (T2). Data was analyzed using linear mixed-effects model as primary analysis and two-way repeated-measures analysis of variance as supportive.

In the primary mixed-effects analysis, implant stability did not differ significantly between the PBM and control groups at baseline (estimated mean difference [PBM control], -2.45 ISQ; P = 0.341). At 2 months, PBM-treated implants demonstrated significantly higher estimated stability than control implants (mean difference, 6.30 ISQ; 95% CI, 1.21-11.39; P = 0.016). At 3 months, no significant between-group difference was observed (mean difference, 0.40 ISQ; P = 0.878). The linear mixed-effects model demonstrated a significant time × treatment interaction (P = 0.042), indicating that implant-stability trajectories differed between the groups over time. The complete-case repeated-measures ANOVA yielded a consistent significant time × treatment interaction (P = 0.007). No adverse effects related to PBM were observed.

Photobiomodulation using a 940-nm diode laser enhanced early implant stability and reduced the magnitude of the stability dip in D3-D4 maxillary bone without affecting final implant stability after 3 months. PBM may represent a safe adjunctive approach to support early osseointegration in low-density bone.